Investigation Of Hardness Anisotropy In Tourmaline
Affiliation(s)
Department of Metallurgical and Materials Engineering,Obafemi Awolowo University,Ile-Ife.Nigeria. Engineering Materials Development Institute, Akure, Nigeria.
Department of Metallurgical and Materials Engineering,Obafemi Awolowo University,Ile-Ife.Nigeria. Engineering Materials Development Institute, Akure, Nigeria.
ABSTRACT
Tourmaline is a ring silicate material with a hexagonal crystal structure. Tourmaline crystal is made use of as an electronic component, e.g, as a transducer, mainly because of the anisotropy it exhibits in its properties. Microindentation technique was employed in the research reported in this paper, using a Knoop indenter, to investigate the anisotropy in the hardness of the tourmaline crystal on its two major crystallographic planes: (0001) and {10 1 0}. The material was found to exhibit hardness anisotropy in conformity with its rotary symmetry elements. The material was identified and analysed using various x-ray techniques, and was found to contain some impurities as expected of natural crystals. Tourmaline was found to have a Si/Al ratio of 1.4. The orientations of the crystal samples were determined by obtaining and indexing the Laue x-ray back-reflection patterns of the crystal samples.
Tourmaline is a ring silicate material with a hexagonal crystal structure. Tourmaline crystal is made use of as an electronic component, e.g, as a transducer, mainly because of the anisotropy it exhibits in its properties. Microindentation technique was employed in the research reported in this paper, using a Knoop indenter, to investigate the anisotropy in the hardness of the tourmaline crystal on its two major crystallographic planes: (0001) and {10 1 0}. The material was found to exhibit hardness anisotropy in conformity with its rotary symmetry elements. The material was identified and analysed using various x-ray techniques, and was found to contain some impurities as expected of natural crystals. Tourmaline was found to have a Si/Al ratio of 1.4. The orientations of the crystal samples were determined by obtaining and indexing the Laue x-ray back-reflection patterns of the crystal samples.
Cite this paper
M. Adeoye and O. Adewoye, "Investigation Of Hardness Anisotropy In Tourmaline," Journal of Minerals and Materials Characterization and Engineering, Vol. 3 No. 2, 2004, pp. 99-103. doi: 10.4236/jmmce.2004.32011.
M. Adeoye and O. Adewoye, "Investigation Of Hardness Anisotropy In Tourmaline," Journal of Minerals and Materials Characterization and Engineering, Vol. 3 No. 2, 2004, pp. 99-103. doi: 10.4236/jmmce.2004.32011.
References
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[1] Adewoye O. O. Anisotropy flow and fracture in beryl [Be3Al2(SiO3)6]. J. Mater. Sci. 21, 1161. 1986 [2] Adewoye O. O. and Page T. F. The anisotropy behaviour of etched hardness indentation in SiC. J. Mater. Sci. 11, 981.1976 [3] Henry D. J. and Guidotti C. V. Tourmaline as a petrogenetic indicator mineral: An example from the straurolite-grade metapelite of NW Maine. Am. Mineralogist 70, 1.1985 [4] Deer W. A., Howie R. A. and Zussman J. “Rock-Forming Minerals.” Vol. 1B:Disilicates and Ring Silicates. 2nd edition. London, Longman Group Ltd. 1986 [5] Deer W. A., Howie R. A. and Zussman J. “An Introduction to the Rock-Forming Minerals.” England, Longman Scientific and Technical. 1992 [6] Phillips F. C. “An Introduction to Crystallography.” Fourth edition. English Language Book Society and Longman Group Limited. 1971 [7] Klein C. and Hurlburt jr. C. S. “Manual of Mineralogy.” New York, John Wiley and Sons, Inc. 1993 [8] Cullity B. D. “Elements of X-Ray Diffraction.” 2nd edition. Addison-Wesley Publishing Company, Inc.. 1978 [9] Kelly A. and Groves G. W. “Crystallography and Crystal Defects.” London, Longman Group Limited. 1970 [10] International Union of Crystallography “International Tables for X-ray Crystallography” Vol. I: Symmetry Groups. Henry N. F. M. and Lonsdale K. (eds.) Birmingham, England, Kynoch Press. pp.15 - 21. 1969 [11] Katz R. N. “Proceedings of the Third International Conference on Mechanical Behaviour of Materials.” Volume I. Miller K. J. and Smith R. F. (eds.) 20th August, 1979. Pergamon Press. 1980 [12] Sargent P. M. Ph. D. Thesis: Factors Affecting The Microhardness of Solids. University of Cambridge, England. 1979 [13] Longhurst R. S. “Geometrical and Physical Optics.” London, Longman Groups Limited. 1973 [14] Adeoye M. O. Ph.D. Thesis: Flow And Fracture in Tourmaline and Beryl Using Indentation Techniques. Obafemi Awolowo University, Ile-Ife, Nigeria. 1998